If a client's blog hosting platform is only able to provide them with an RSS feed link (and they are unwilling to explore other options on their own), you can suggest utilizing a third-party website that allows them to create a widget using their RSS feed link.
Here is an example website they can try (they may need to sign up first): http://feed.mikle.com/
After they input their RSS link, they should then be able to copy the embed code provided and paste it into the source code of the blog home page, or whichever page on the website they would like their blog content to appear.
To learn more about adding to the source code of a page, click here.